Spark-plug.



To ll 'it may concern:

i STATES PAT-Enrrermon.

- Imm N. EASTMAN, ornnY'roiLoHIo, nssrenon or ONE-HALF 'ro Emms'r A..

.. Merriam or DAYTON, omo.

SPARK-PLUG.

'Appntation mea march 2o, 1915. sealara. 5679.

Be'tknown that I, HARRY N. E As'rnnn,

citizen ofthe United States, residing vat.

vDayton, in the county ofI Montgomery and 'State'of Ohio, have 'inventedcertain new and usefullmprovements in Spark-Plugs,

' of which the following is a speciiication.

.4 My invention relates to explosive engines and morepanticularly toignition orspark `plugs therefor.

* The object of the invention-is to simplify the structure of suchdevices whereby they ,not only be cheapenedin construction,.

but'will bel more efficient in use, capable of being easily and quicklydisassembled and assembled, compression tight and unlikelyv to et out ofrepair.

further object of the invention is to provide limproved-form ofinsulation which will eectuallyprevent short` circuitin in the at theorcelain core is bro. en.

' 'A her ob] ect ofthe invention is to provide an improved form ofelectrode whereby a broad fat -spark will be induced.

With the above primary and'other incidental objects in viewkas will morefully gap:

pear in the? specification, the invention con- -sists of lthe featurfofconstruction, :the

parts Yand combinations thereof, and the modev of operationor theirequivalents .as hereinafterl described and set forth in the claims. l

In the tion of the assembled spark .plug forming the subjectmatterfihereof. Fig. 2 is a longitudinal sectionalview of the same.

-Like partsy are indicated by similar characters of reference.throughout the several views.

. Referring to the' draw1ngs, 1 1s the main bushing V@i5l'p'risi'ng ahexagonal headland a screw threaded extension 2 .adapted 'to be\\engaged jin the wall of the engine cylinder .or in Cthegignition.chamber. thereof, The

mainbushing 1 is A counter bored t"f rm therein'VV a seat or shoulder 3.

Extending within the bushing 1 ffrbm the inner or screw .threaded endthereof is a core .4 fporcelain,

fire clay, glass, or/Jother suitable material. This core 4 isprovidedwithl a conical truncated head l,i3/which proJects peripherally beyondthe main body of .the 4 forming'a flange or seat 6 engaging upon theextremity of the screwthr'eaded ex- .tensionof the lmain bushing l.Interposed j drawings, Figure lis a side elevabetweenl the seat'orflange 6 of the core and.

the extremity of the bushing is a gasket-or 'specimenanfangen.'IPatented Nov. 2,1, 1916.-.

washer 7 preferably of copper or some other comparatively soft but heatresisting mate- .or depression -9 into which the lower end of theinsulating sleevev 8 projects above the level of the seat 3 within thebushing.,

Surrounding the upper portion of the core 4 and projecting within'the1enlarged portion of the bore of the bushing is a second sleeve 10 ofinsulating material seatedupon the shoulder or oiset 3 of the bushing.The

first mentioned insulating sleeve 8 extends within the latter sleeve 10andl forms therewith a telescopic joint, as indicated at 11.

The core 4 is provided with a central bore through which extends theprimaryelectrode 12. This electrode isin thefzform of'a bolt having atoneend a head 13, the diameter of which corresponds with that of theapex of the conical head 5. Interposed between the head 13 and-the apexof the conical head 5 of the core is a gasket or washer 14 of copper orother comparatively soft heat resisting material. The head 13 isvpreferably circular and provided with parallel. side walls.- The shaftof the electrode .extends throughthe bore of the core 4 and is screwthreaded'at its upperend to receive a compression disk 15 which bearsupon the upper end of the insulating sleeve 10. vBy' tighteningthecompression disk 15 the several parts are firmly lsecured together.`The insulating sleeve 10, bearing upon the shoulder or o'set 3, forms anabutment for draw#v ing the head 5 of the core tightly into en gagementwith the lower end of the extension v2l of the bushing by the tighteningof the compression disk 15 upon the shaft of the electrode. In orderthat the telescopic sleeves 8 and 10 may oifer no resistance to thetightening of the parts," a 'slight clearance or play is provided for inthe telescopic or interlocking joint,.as indicated at 16.

` rIt has been .found in practice that the roughv usage to which sparkplugs embodylarly Tala ing porc used upon automobile motors, ....celeincore is frequently cracked by jar, heat, or concussion and or broprevent arc-ing or short circuiting in the event that the porcelain core'e is fractured or broken.

The usual binding screw 17, on the upper' end ot the electrode l2,serves as a lock nut to secure the parts in their ad]usted posi- -tion.Projecting from the inner edge of the' screvv threaded extension 2 is asecond electrode or terminal linger 18 which entends first parallel withthe axis of the spark plug, then angularly inward, and terminates inlaportion extending parallel with the anis of the' plug and spacedslightly :may :from but in the saine plane with the head i3 oi' heprimary electrode. This terminal portion of the linger or secondaryelectrode' extends parallel with the face or periphery of the head'l,thereby adording an extended area' across which the spark may arc. This,construction "ad'ordsy a Wide ribbon-like spark of great intensity. Thehead' 13, being of comparatively large size, will reni-ain comparativelyclean and will not collect soot or carbon to interfere withthelquality'* of the spark, as is the cascwhen 'the spark is caused tojump from one point to another. The fact that the spark leaves thesecondary' electrode in a lateral directionand not from the end orterminal thereof, likewise reduces the diiiculty due to clogging of thespark plug u'ith soot, carbon, or other products of con'ibustion.

From the above description it will be apparent that there is'thusprovided a deric'e oi' the character described. possessing theparticular Aeatures of advantage before enumerated as desirable 'butwhich obviously is susceptible ci' modification in its form, proportion,nient oi partsv` Without departing -from the principle involved orsacrificing any ol its advantages A lliile in order to comply 'with thestatute the invention has been described in lane guage more or lessspecific as to certain structural features. it is to be understood thatthe invention is not limited to any speein cores are subjected, particutet, in such 'case the ignition circuit is tre-v,

lThe present detail construction or arrange- Y the electrons Having thusdescribed my nivention, claim:

l.. En spark plug comprising a bushing having an internal lshoulder orseat therein,

a core, an electrode Within the core, a sep- .arable 'sleevev ofinsulating material surrounding the core and engaging atene end theshoulder or seat Within the bushing, a seat for a second insulating-sleeve formed in said'rst .mentioned sleeve, and a second sleeve or"insulating materiel also surrounding the core and seated Withinthe*iirst men- 'tioned sleeve.

2. ln av spark plug, a seriesof telescopic members each independently'movable and each seated upon the other in adjusted iposit-ioncomprising a main bushing, a seat thereon, a sleeveoltinsulatingmaterialslidably mounted in said bushing and engaging saidseat, a seat on said sleeve, a second sleeve of insulating material alsoslidably mounted vin said bushing and engaging the seat upon the rstmentioned sleeve, va core slidably mounted within the said sleeves, aiseat on said core engaging the last inentioned sleeve, and means forretaining said parts'in adjusted positions.

3. A spark plug comprising a bushing having an internal shoulder or seattherein, a core 'within the bushing having an external shoulder, asleeve of insulating material surrounding the core and engaging at oneend upon the shoulder Within the bushing., a secondsleeve ot insulatingmaterial surrounding the core and engaging the shoulder thereof, and,abutting upon the rst mentioned sleeve at its opposite end, land means.for retaining the parts in adjusted positions. y i

el.. A spark plug comprising a lnishing haring an internal seat orshoulder, av core therein ha Ting a truncated conical head 'forming ashoulder upon the core', a sleeve ct insulating material surrounding thecore and engagingthe bushing shoulder, a second sleeve ot insulatingmaterial surroundino" the core and engaging the head and shoulderthereof, said second sleeve being telescopically connected with the irstsleeve, an elect-rode extending through the core. a head on saidelectrode registering *with the apex or the truncated head of the core,and an adjusting member screnv threaded upon engaging the. irst nienntioned sleeve.

spark plug comprising a bushing, a

y core VWithin the bushing haring' a truncated.

las

groove therein, a sleeve of insulatingmeteconcentric groove of the corehead and the rial Within the bushing and surrounding other end thereofprojecting above the the core, saidsleeve projecting into theconbushing, making a continuous body of in- 1 centric grooveof the corehead, and an elec-A sulation, both ends extend-ing beyond the 15 5ltrode extending through the core. bushing.

"f6. :A spark plug comprising a bushing, a. In testimonv'whereof, I havehereunto set core Within the bushing having a truncated my hand this15th day of March, A. D. 1915.

conical head, said head havinga concentric HARRY N. EASTMAN. groovetherein,` insulating materiel Within Witnesses: 7 0 the bushing andsurroundingthe core, one ALFRED MGCRAY,

end of said material projecting into the CARRIE M.- BECKER.

